For any given release of Windows, there are companies that choose to skip it. But when the company is Intel, it's a big deal. Intel's IT department "found no compelling case" for upgrading to Windows Vista.

The thing is, if you buy a modern machine, you need an os that will take advantage of the power. What use is your NVidia 9600 GTX card, or 8 gigs of ram if you are browsing the web?

Vista have very aggressive caching to make the apps you use more responsive. It has self diagnostic processes, and indexers. All three of these mean fairly consistent disc I/O. If you have a fast HD, chances are you wont notice it. If you have an old IDE HD, Vista will slow to a crawl.

Ditto with the video card. You are actually saving CPU with Aero, because you are using a computer resource that typically goes almost idle when you aren't gaming or doing graphics work. Sure, if you have a shoddy vid card, Aero will just slow everything down. If you have modern hardware though, you aren't really getting penalized for the improved experience.

I have installed XP on my home machine for testing purposes, and honestly, I only noticed the slightest of differences overall. For me personally, the only time I feel a noticeable lag from vista is when i am using Visual Studio, which is probably the most I/O intensive app on the planet. Because of that I tone down the indexers on my dev machine (only indexes the start menu). I am planning on getting a new rig soon though, and my number one requirement is RAID-0 SATAIII 7200rpm configuration, which I am pretty sure will make studio fly.

This is why I always tell people not to bother buying a new machine for vista, but when they do get a new machine that it will be a nice upgrade. This is the first version of windows I find has an acceptable level of polish, and while it is far from my favorite operating system out there, I really don't mind using it to make my living.

Vista have very aggressive caching to make the apps you use more responsive. It has self diagnostic processes, and indexers. All three of these mean fairly consistent disc I/O. If you have a fast HD, chances are you wont notice it. If you have an old IDE HD, Vista will slow to a crawl.

The self indexing might have been called a beneficial feature if it didn't have such hideous counter-intuitive interface. (Most Vista users that I know simply disable it)
As it stands, it just eats away IO and CPU time.

Ditto with the video card. You are actually saving CPU with Aero, because you are using a computer resource that typically goes almost idle when you aren't gaming or doing graphics work. Sure, if you have a shoddy vid card, Aero will just slow everything down. If you have modern hardware though, you aren't really getting penalized for the improved experience.

Gaah. I know what you mean... but... Nope.
Power-wise, even a low-end GPU will spend far more power on the 3D interface then the CPU cycles required by XP/Linux/etc to draw their 2D interface.

I have installed XP on my home machine for testing purposes, and honestly, I only noticed the slightest of differences overall. For me personally, the only time I feel a noticeable lag from vista is when i am using Visual Studio, which is probably the most I/O intensive app on the planet.

I wouldn't call VS I/O intensive - unless you're building huge projects 24x7 (And if you are, you should consider switching to a GNU Makefile instead of using project files - distributing the builds to multiple concurrent jobs.)
Try testing the same application on 6 different VM guests on the same host and you'll see what I/O intensive means...

Because of that I tone down the indexers on my dev machine (only indexes the start menu). I am planning on getting a new rig soon though, and my number one requirement is RAID-0 SATAIII 7200rpm configuration, which I am pretty sure will make studio fly.

Then again, having the CPU spent on building your code is better then having it spent on Vista tasks, don't you agree?

This is why I always tell people not to bother buying a new machine for vista, but when they do get a new machine that it will be a nice upgrade. This is the first version of windows I find has an acceptable level of polish, and while it is far from my favorite operating system out there, I really don't mind using it to make my living.

My advise to Windows-using-friends (As I said, I'm a Linux users and I use Windows [XP/Vista/2K3] just to test my software) is more-or-less the same:
Don't upgrade unless you have to, but buy Vista compatible hardware once you do. (Even-though I recommend against using Vista as long as XP is alive and well)

Even though I'm far from being a tree-hugging-environmentalist (Especially given the fact that I'm currently building a dual Xeon as my next home workstation...) I still dislike the idea of spending money and electricity just to run a bare OS. To each its own, I guess...

I wouldn't call VS I/O intensive - unless you're building huge projects 24x7 (And if you are, you should consider switching to a GNU Makefile instead of using project files - distributing the builds to multiple concurrent jobs.)
Try testing the same application on 6 different VM guests on the same host and you'll see what I/O intensive means...

Not gonna respond to the other stuff, since we seem to sort of be going in circles, but I have to call you on this. VS is constantly doing partial compilation of classes, almost after every line. I also use a plugin from jetbrains called Resharper, which only adds to the problem since it makes the whole thing more aggressive.

Fire up procmon and look at what studio does some time, even when it is just idling. It is right up there in resource usage.